No. 4.] HOW TO BUY FERTILIZERS. 219 



HOW TO BUY FERTILIZERS. 



MR. R. E- ANNIN, JR. 



All plants require ten elements for their growth. These 

 are carbon, hydrogen, ox^^gen, nitrogen, iron, snlphnr, cal- 

 cium, magnesium, phosphorus and potassium. The first 

 four are gases, and three of them — carbon, hydrogen and 

 oxygen — are secured by the plant from the air and water 

 without the necessity of any aid from man. Of the six 

 elements which come from the soil, iron, sulphur and mag- 

 nesium are usually present in sufficient quantities and avail- 

 able forms in practically all soils. Continuous cropping, 

 however, has brought most soils in Massachusetts to the point 

 where nitrogen, phosphorus and potassium are not present in 

 large enough available quantities to produce maximum crops. 

 They may be called the essential fertilizing elements. Cal- 

 cium (lime) is rarely needed as a fertilizing element, but is 

 often needed as a soil amendment ; that is, to sweeten sour 

 soils and make heavy soils more friable. It may, therefore, 

 be called an occasional fertilizing element. 



In buying commercial fertilizers, therefore, farmers are 

 buying nitrogen, phosphorus and potassium in highly con- 

 centrated form. A few things that commercial fertilizers 

 can and cannot do should be kept clearly in mind. 



1. Some of them, such as dried blood and cottonseed meal, 

 do add some organic matter (humus) to the soil, but only a 

 small part of what is needed. 



2. They will not correct poor drainage conditions. 



3. They will not overcome bad results due to poor seed, 

 improper planting or careless methods. 



4. They may have a slight good or bad effect on the 

 physical condition of the soil, according to how they are 

 compounded. 



